1. Field of the Invention
The present invention relates to a removable data storage device.
More specifically, the invention relates to a removable storage device comprising at least one substrate whereon a plurality of components are arranged.
More in particular the present invention relates to a removable data storage device of the USB type and the following description is made with reference to this field of application by way of illustration only.
2. Description of the Related Art
As it is well known, data storage devices of the removable type, such as USB peripherals (acronym of the English: “universal serial bus”) or Flash cards, are currently realized by mounting, on small and thin printed circuit boards or PCBs (acronym of the English: “printed circuit board”), silicon-based components incorporated in suitable packages, such as memories and ASICs (acronym of the English: “application specific integrated circuit”) just as non-silicon components, such as passive components and crystals.
To assemble these components traditional assembling techniques are generally used for PCBs, remarkably improved in time but however always limited due to the physical constraints linked to the dimensions of the single packages and to the physical realization of the PCB itself. These constraints impose in particular limits to the reduction of the integration scale of the storage devices as a whole.
On the contrary, market needs currently require data storage devices with higher and higher densities and lower and lower form factors, up to the desired limit of the hard disk on silicon.
This trend is also followed by packaging technologies offering very complex and state-of-the-art approaches to decrease the dimensional impact of the single packages.
In particular, using these “packaging” technologies is known for the manufacturing of MMC™ boards (acronym of the trademark: “MultiMediaCard™”) providing, after a molding process similar to the one used to obtain an SMD component (acronym of the English “Surface Mounted Device”) and wherein the separation (singling) of each package is carried out by means of mechanical blanking before the application of a cover, that the final packaging step is carried out by using a supplemental plastic cover which is constrained, by means of adhesive, to a substrate of the MMC board and to the forming mold.
A package is thus obtained which can be shaped according to a specific profile, as needed for MMC boards. In particular, rounded edges are obtained with a suitable shape of this plastic cover.
It is however remarked that, even if this advanced packaging technology allows one to use a manufacturing line of SMD components also for the manufacturing of MMC boards, some difficulties in the singling and finishing operations remain.
In these last years, remarkable progresses have been made in the laser cutting process on organic materials such as the material as substrate. The laser cutting is a very interesting solution for the singling of MMC boards, especially because the profile is neither squared nor rectangular.
However, the problem of obtaining rounded edges remains, and the standard laser cutting technique does not ensure this particular shaping of the substrate whereon the MMC board is realized.
In general, these technologies are extremely expensive and they are currently used only for devices with very high density having a very high cost in terms of silicon and thus not suffering, in their final price, from the packaging costs.
The same approach has thus not been used so far for low density storage devices for which the impact of the packaging cost would be comparable to the cost in silicon and thus non realistic on an industrial scale.
Storage devices of the USB type, i.e., devices using communication protocols according to this USB standard, are the most diffused and the most suitable ones to realize removable storage devices with high density, in other words the desired removable hard disk.